Cam isolator for common lock memory system

ABSTRACT

A common lock memory mechanism for a pushbutton tuner includes a spring washer positioned between each spacer and an adjacent cam to provide sufficient friction to hold the cams in position with respect to the shaft with the common lock unlocked. A wave or star washer is located between adjacent spacers to prevent movement of the spacers with respect to each other with the common lock unlocked except the selected cam is rotated to set the same to a desired station in response to actuation by the associated pushbutton.

United States Patent 1 [111 3,744,323 Olah [45] July 10, 1973 CAM ISOLATOR FOR COMMON LOCK MEMORY SYSTEM Primary Examiner-Milton Kaufman Attorney-Mueller and Aichele 5 7 ABSTRACT A common lock memory mechanism for a pushbutton tuner includes a spring washer positioned between each spacer and an adjacent cam to provide sufficient friction to hold the cams in position with respect to the shaft with the common lock unlocked. A wave or star washer is located between adjacent spacers to prevent movement of the spacers with respect to each other with the common lock unlocked except the selected cam is rotated to set the same to a desired station in response to actuation by the associated pushbutton.

6 Claims, 8 Drawing Figures Patented July 10, 1973 3,744,323

2 Sheets-Shae: l

INVENTOR. EMERY E. OLAH ATTORNEYS.

Patented July 10, 1973 3,744,323

2 SheetsSheet l INVENTOR EMERY E. OLAH BY Ma ATTORNEYS CAM ISOLATOR FOR COMMON LOCK MEMORY SYSTEM BACKGROUND OF THE INVENTION A common lock for the memory mechanism of a pushbutton tuner is a relatively recent development. In the past each of the memory cams in pushbutton tuners had a separate locking mechanism. However, with the common locking device only one lock is necessary. This lock presses the memory cams and adjacent spacers together to cause them to rotate as a unit.

Setting memory cams to specific positions for tuning to predetermined frequencies, requires that the particular cam being positioned move freely. However, due to the friction between the selected cam and adjacent spacers and cams, there is no assurance that while the common lock is unlocked and a particular cam is positioned, that other cams will not rotate therewith.

SUMMARY OF THE INVENTION It is an object of this invention to provide isolation of memory cams of a common lock tuner mechanism.

It is another object of the present invention to prevent movement of the remaining memory cams with the common lockin the unlocked condition while a selected cam is shifted to a new position.

It is a further object of the present invention to provide means for holding a shifted memory cam in its new position just prior to operating the common locking device to lock the cams in position.

A memory mechanism for pushbutton tuners includes a shaft linked to a tuning mechanism which responds to the rotation of the shaft. The shaft carries a plurality of memory cams and spacers in alternate arrangement. A spring washer separates each spacer from an adjacent memory cam and provides spring bias with the common lock of the memory mechanism unlocked. This spring bias prevents free rotation of each of the memory cams with respect to spacers because of the friction produced. Inthe locked condition the spring washer is further compressed and effectively prevents any movements of the cams with respect to the spacers. A wave or star washer also mounted on the tuning shaft separates the adjacent spacers. The memory cams have bores of a diameter greater than the shaft diameter so that the wave or star washer may be positioned about the shaft between adjacent spacers, and within the bore of the cam which can rotate clear of the washer. The wave or spring washer, whichever is used, prevents movement of the spacers with a selected memorycam being rotated in response to the actuation of its respective pushbutton. Nonselected cams are thus'prevented from moving with the common lock in the unlocked position to misalign the remaining 'preset stations. The spring washer adjacent to a selected memory cam permits rotation thereof in response to actuation by its respective pushbutton yet prevents free rotation after the memory cam has been set, by holding the memory cam in position until the common lock can be switched to the unlocked condition.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the housing of the pushbutton tuner with the memory mechanism of the present invention;

FIG. 2 is a partially exploded perspective view of the common locking mechanism which embodies the present invention;

FIG. 3 is a perspective view of a wave washer used in accordance with this invention;

FIG. 4 is a perspective view of a spring washer used in accordance with this invention;

FIG. Sis an elevation view in partial cross-section of the tuner shaft with the memory mechanism;

FIG. 6 is an enlarged elevation view in partial crosssection of a portion of FIG. 5;

FIG. 7 is a plan view of a star washer; and

FIG. 8 is an elevation view in partial cross-section of a portion of the tuningdevice in accordance with the present invention.

DETAILED DESCRIPTION In the drawings, FIG. 1 shows the housing of a pushbutton tuner for a radio having pushbuttons 12, 14, 16, 1'8 and 20 each of which may be set to a different broadcast station. A switch 22 permits shifting the radio from AM reception to FM and vice versa. An additional switch 24 provides for locking and unlocking the common lock of the memory mechanism.

The memory mechanism for the pushbutton tuner includes a shaft 26 which extends through linkage brackets 28 and 30, the common lock 32 and the spacers 34, 36, 38', 40, 42, 43', 44, 46, 48 and 50, and the memory cams-54,56, 58, 60, 62, 64, 66, 68, and 72. With the common lock 32 in the locked condition, and the switch 22 set for the AM mode, a pushbutton, for example, 14 wi1l, when actuated engage cam 66with the plunger piece 78 to rotate the same with shaft 26 rotating therewith to set the tuning slugs 74 through the cooperative action of the linkage brackets 28 and 30. By shifting to the FM mode, memory cam 68 instead of memory cam 66 would be engaged by plunger piece 78 of pushbutton 14 upon actuation thereof. This dual device provides separate settings for AM and FM modes for each of the pushbuttons. I

Operation of the common lock device can be found in. detail in US. application Ser. No. 149,477, filed June 3, 1971, and assigned to the assignee of this application. However, generally in the locked condition, the common lock 32 presses together the cam holding means, i.e., the spring washers 81 and 84 for example, (see FIGS. 2, 4, 5, 6, and 8, where for explanation purposes in the different embodiments like parts are given like numbers), and the spacer locking means 86 and 88 (FIGS. 3, 5, 6, 7 and 8) along with the memory cams and spacers. End portions and 82 of the shaft 26, the spring 83 and housing 85 form a part of the common lock 32, the housing portion 85 being moved from right to left (FIG. 5) with the common lock 32 being locked andcausing the memory cams to be locked in position.

With the common lock 32 in the locked position, actu- I ation of a memory cam by a pushbutton will cause the shaft 26 to rotate to the preset station. With the common lock in the unlocked position, the axial pressure between the memory cams and spacers due to the spring washers, e.g., spring washer 84 between spacer 46 and cam 66 (FIG. 5), prevents rotation of the memory cams about the shaft. Also, in the unlocked position the washer between adjacent spacers, whether it be a wave washer 86 (FIG. 3) or a star washer 88 (FIGS. 7 and 8), prevents the adjacent spacers such as spacers 44 and 46 (FIGS. 2, 5 and 6) from rotating relative to each other. Cam 66, with a portion of spacer 46 extending into a bored hole therein, is prevented from moving by the axial pressure of spring washer 84 in conjunction with spacers 46 and 44 and the cam 66 itself.

With the common locking device unlocked, the cam 66, for example, is positioned by pushbutton 14 with the associated plunger piece 78 to the station set by the tuning slugs 74 which may be positioned by manual tuning. Cam 66 rotates about the axis to coincide with plunger piece 78 without spacers 46 and 44 or either one of them rotating therewith. The braking torque which must be overcome before the cam will rotate is less than that necessary to cause a spacer to rotate. A ratio of 5:1 of the braking torque which must be overcome to rotate the spacers with respect to the braking torque which must be overcome for rotating the cams provides a safety factor which has been calculated to give good results. Consequently, the nonselected cams will not rotate to new positions. Since there is no free rotation, vibration will not cause the channels to become reset. The combination of the cam holding means, such as spring washer 84 and the common locking means provides for positioning the selected memory cams in the unlocked condition, the holding of such a position while in the unlocked condition, and preventing the positioning of the selected cam from affecting the position of any other cam of the memory mechanism.

The star washer shown in FIGS. 7 and 8 provides an alternative embodiment to the wave washer. The star washer is provided with ears including 90 and 92 which alternate in displacement from the plane of the washer (see FIG. 8). The ears 90 and 92 engage respective adjacent spacers 94 and 96 by digging into the soft steel thereof. FIG. 8 shows a portion of the memory mechanism in its locked condition with the ears 90 and 92 of the star washer 88 engaging recessed portions 98 and 100 of spacers 94, 96, respectively.

What has been described therefore is a simple device for isolating memory cams in a common lock memory system for selective repositioning thereof.

I claim: V

1. In a memory mechanism for pushbutton tuners including a shaft, means for mounting the shaft, tuning linkage means connected to and responding to rotation of the shaft, a plurality of memory cams axially positioned about the shaft, a plurality of movable spacer means adjacent to and separating the memory cams, a plurality of pushbutton means, each cam being selectively engaged by respective pushbutton means for rotation about the axis of the shaft upon actuation thereof, common locking means having locked and unlocked conditions, said common locking means in a locked condition actuating the spacer means for locking the cams in a fixed position on the shaft, said spacer means in an unlocked condition actuating the spacer means to permit movement of the cams, the combination including first washer locking means positioned between the memory cam and spacer for providing sufficient friction to hold the cam in position relative to said spacers adjacent to said cam with the common lock in the unlocked condition, and second washer locking means positioned between the memory cam and the shaft and between adjacent spacers for preventing relative movement between said spacers with the common locking means in the unlockedcondition so that with a selected one of said cams being rotated to a predetermined position in response to actuation of the respective pushbutton means, said first and secondwasher locking means prevents movement of the nonselected cams.

2. The combination according to claim 1 wherein said second washer locking means comprises a friction lock.

3. The combination according to claim 1 wherein said second washer locking means comprises a star washer.

4. The combination according to claim 1 wherein said second washer locking means comprises a wave washer.

5. The combination according to claim 1 wherein said first washer locking means comprises a spring washer.

6. In a memory mechanism for pushbutton tuners including a shaft, means for mounting the shaft, tuning linkage means connected to and responding to rotation of the shaft, a plurality of memory cams axially positioned about said shaft, a plurality of spacers adjacent to and separating said memory cams, a plurality of pushbuttons, each cam being engaged by a respective pushbutton for rotation about the axis of the shaft upon actuation thereof, common locking means for actuating the spacers for locking the cams in a fixed position on the shaft and unlocking the same, the combination including a spring washer positioned between each spacer and an adjacent cam for providing sufficient friction to hold the cam in position relative to said spacers adjacent to said cam with the common lock in the unlocked condition, and a star washer positioned between the memory cam and the shaft and between adjacent spacers for preventing relative movement of said spacers with a selected one of said cams in said unlocked condition being rotated to position the same in response to actuation of said respective pushbutton thereby preventing movement of the nonselected cams.

* alt 

1. In a memory mechanism for pushbutton tuners including a shaft, means for mounting the shaft, tuning linkage means connected to and responding to rotation of the shaft, a plurality of memory cams axially positioned about the shaft, a plurality of movable spacer means adjacent to and separating the memory cams, a plurality of pushbutton means, each cam being selectively engaged by respective pushbutton means for rotation about the axis of the shaft upon actuation thereof, common locking means having locked and unlocked conditions, said common locking means in a locked condition actuating the spacer means for locking the cams in a fixed position on the shaft, said spacer means in an unlocked condition actuating the spacer means to permit movement of the cams, the combination including first washer locking means positioned between the memory cam and spacer for providing sufficient friction to hold the cam in position relative to said spacers adjacent to said cam with the common lock in the unlocked condition, and second washer locking means positioned between the memory cam and the shaft and between adjacent spacers for preventing relative movement between said spacers with the common locking means in the unlocked condition so that with a selected one of said cams being rotated to a predetermined position in response to actuation of the respective pushbutton means, said first and second washer locking means prevents movement of the nonselected cams.
 2. The combination according to claim 1 wherein said second washer locking means comprises a friction lock.
 3. The combination according to claim 1 wherein said second washer locking means comprises a star washer.
 4. The combination according to claim 1 wherein said second washer locking means comprises a wave washer.
 5. The combination according to claim 1 wherein said first washer locking means comprises a spring washer.
 6. In a memory mechanism for pushbutton tuners including a shaft, means for mounting the shaft, tuning linkage means connected to and responding to rotation of the shaft, a plurality of memory cams axially positioned about said shaft, a plurality of spacers adjacent to and separating said memory cams, a plurality of pushbuttons, each cam being engaged by a respective pushbutton for rotation about the axis of the shaft upon actuation thereof, common locking means for actuating the spacers for locking the cams in a fixed position on the shaft and unlocking the same, the combination including a spriNg washer positioned between each spacer and an adjacent cam for providing sufficient friction to hold the cam in position relative to said spacers adjacent to said cam with the common lock in the unlocked condition, and a star washer positioned between the memory cam and the shaft and between adjacent spacers for preventing relative movement of said spacers with a selected one of said cams in said unlocked condition being rotated to position the same in response to actuation of said respective pushbutton thereby preventing movement of the nonselected cams. 